Receiver (2) sequentially switches a preset frequency change amount in stages from a large value to a small value. According to the reception side frequency change amount, the reception side frequency candidate for detecting a synchronization signal is calculated. Synchronization signal detection unit (5) detects a synchronization signal transmitted from a transmission device by using the calculated reception side frequency candidate. Moreover, transmitter (1) calculates a transmission side frequency candidate as a frequency candidate for transmitting the synchronization signal according to the largest possible frequency change amount calculated according to the bandwidth of the synchronization signal. When the calculated transmission side frequency candidate exists in the system frequency band, the calculated transmission side frequency candidate is determined to be a synchronization signal frequency for transmission of the synchronization signal, and the synchronization signal is transmitted from synchronization signal transmission unit (4) to receiver (2).
Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A communication system comprising a transmission device for transmitting a synchronization signal for establishing synchronization, and a reception device for establishing synchronization by detecting the synchronization signal, wherein said reception device sequentially changes intervals from long intervals to shorter intervals at which an attempt is made to detect the synchronization signal, said transmission device is set to transmit the synchronization signal at long intervals of said reception device, said synchronization is frequency synchronization, and said establishment of synchronization includes detecting an effective communication frequency, said reception device sequentially switches a preset frequency change amount from a larger value to a smaller value in stages, calculates a reception side candidate frequency for detecting the synchronization signal based on the frequency change amount, and detects the synchronization signal using the calculated reception side candidate frequency, and said transmission device calculates a transmission side candidate frequency which is a candidate for a frequency for transmitting the synchronization signal, based on the largest possible frequency change amount calculated on the basis of a system bandwidth in which said communication system communicates, and determines the transmission side candidate frequency as a synchronization signal frequency for transmitting the synchronization signal when the transmission side candidate frequency exists within the system frequency band.
A communication system synchronizes a transmitter and receiver. The receiver searches for a synchronization signal by checking frequencies at progressively finer intervals (large to small). The transmitter sends the sync signal at the receiver's longest search intervals. Synchronization involves finding a usable communication frequency. The receiver narrows down its frequency search by stepping through frequency offsets, from large to small, calculating and testing candidate frequencies. The transmitter calculates candidate transmission frequencies based on the system bandwidth, and if a candidate falls within the allowed band, it uses that frequency to transmit the synchronization signal.
2. The communication system according to claim 1 , wherein: said reception device adds an offset to an integer multiple of the reception side frequency change amount to generate the reception side candidate frequency, and said transmission device adds an offset to an integer multiple of the transmission side frequency change amount to generate the transmission side candidate frequency.
In the communication system, to find the synchronization signal, the receiver generates candidate frequencies by adding an offset to multiples of its frequency change amount. Similarly, the transmitter generates its candidate frequencies by adding an offset to multiples of its frequency change amount. This allows for a finer-grained search for the correct frequency.
3. The communication system according to claim 2 , wherein: said reception device sets the offset to zero, and said transmission device sets the offset to zero.
In the communication system, both the receiver and transmitter simplify their frequency calculations by setting the offset to zero when generating the candidate frequencies. The receiver generates candidate frequencies as integer multiples of the reception side frequency change amount and the transmitter generates candidate frequencies as integer multiples of the transmission side frequency change amount.
4. The communication system according to any one of claims 1 , 2 and 3 , wherein: said transmission device transmits a known signal as the synchronization signal, and said reception device detects matching the reception side candidate frequency with the known signal or with a replica signal calculated from the known signal using IFFT or FFT, and stores the calculated replica signal.
In the communication system, the transmitter sends a known, predetermined signal as the synchronization signal. The receiver detects the sync signal by comparing its candidate frequencies to this known signal. The receiver can either directly compare to the signal, or compare against a replica signal pre-calculated from the known signal using Inverse Fast Fourier Transform (IFFT) or Fast Fourier Transform (FFT) techniques, and stores the pre-calculated replica signal for fast matching.
5. The communication system according to any one of claims 1 , 2 and 3 wherein: said transmission device transmits a signal which repeats the same pattern as the synchronization signal, and said reception device detects the synchronization signal through a delay detection.
In the communication system, instead of a unique signal, the transmitter sends a repeating pattern as the synchronization signal. The receiver detects this synchronization signal by looking for the repeated pattern in the received signal, using a delay detection method that identifies the correlation between the signal and a delayed version of itself.
6. The communication system according to any one of claims 1 , 2 and 3 , wherein: said transmission device sets the transmission side frequency change amount to an integer multiple of a minimum placement of a center frequency of the system band.
In the communication system, the transmitter sets its transmission frequency change amount to a multiple of the minimum spacing or resolution of the system's center frequency. This ensures that the transmission frequency candidates align with the system's frequency grid, facilitating efficient synchronization.
7. The communication system according to any one of claims 1 , 2 and 3 wherein: said reception device sets the reception side frequency change amount to an integer multiple of a minimum placement unit of a center frequency of the system band.
In the communication system, the receiver sets its frequency change amount to a multiple of the minimum spacing or resolution of the system's center frequency. This ensures that the receiver's frequency search aligns with the system's frequency grid, facilitating efficient synchronization.
8. A transmission device for transmitting a synchronization signal to a reception device for establishing synchronization within a system frequency band, wherein: said transmission device calculates a transmission side candidate frequency which is a candidate for a frequency for transmitting the synchronization signal based on a largest possible transmission side frequency change amount calculated on the basis of a bandwidth of the synchronization signal, and determines the transmission side candidate frequency as a synchronization signal frequency for transmitting the synchronization signal when the transmission side candidate frequency exists within the system frequency band.
A transmitter sends a synchronization signal to a receiver. The transmitter calculates potential transmission frequencies based on the largest possible frequency change amount derived from the bandwidth of the synchronization signal. If a calculated transmission frequency falls within the acceptable system frequency band, the transmitter uses that frequency to send the synchronization signal.
9. The transmission device according to claim 8 , further comprising: adding an offset to an integer multiple of the transmission side frequency change amount to generate the transmission side candidate frequency.
The transmitter calculates its potential transmission frequencies by adding an offset to multiples of its frequency change amount. This adds flexibility in selecting the optimal frequency for synchronization within the available bandwidth.
10. The transmission device according to claim 9 , further comprising: setting the offset to zero.
The transmitter simplifies its frequency calculation by setting the offset to zero when generating the candidate frequencies for transmission. Candidate frequencies are generated as integer multiples of the transmission side frequency change amount.
11. A reception device for receiving a synchronization signal transmitted from a transmission device, wherein: said reception device sequentially switches a preset reception side frequency change amount from a larger value to a smaller value in stages, calculates a reception side candidate frequency for detecting the synchronization signal based on the reception side frequency change amount, and detects the synchronization signal using the calculated reception side candidate frequency.
A receiver receives a synchronization signal. The receiver checks frequencies at progressively finer intervals (large to small). It calculates candidate frequencies for detection based on the reception side frequency change amount, and then checks each candidate frequency to detect the synchronization signal.
12. The reception device according to claim 11 , further comprising: adding an offset to an integer multiple of the reception side frequency change amount to generate the reception side candidate frequency.
The receiver generates candidate frequencies by adding an offset to integer multiples of the receiver's frequency change amount. This offset allows for a finer-grained search for the correct frequency.
13. The reception device according to claim 12 , further comprising: setting the offset to zero.
The receiver simplifies its frequency calculations by setting the offset to zero when generating the candidate frequencies for reception. Candidate frequencies are generated as integer multiples of the reception side frequency change amount.
14. A synchronization method in a communication system comprising a transmission device for transmitting a synchronization signal for establishing synchronization within a system frequency band, and a reception device for detecting the synchronization signal within the system frequency band, said method comprising: processing performed by said reception device to sequentially change intervals from long intervals to shorter intervals at which an attempt is made to detect the synchronization signal; processing performed by said transmission device to set a transmission such that the synchronization signal is detected at the long intervals of said reception device; processing performed by said reception device to sequentially switch a preset frequency change amount from a larger value to a smaller value in stages; processing performed by said reception device to calculate a reception side candidate frequency for detecting the synchronization signal based on the reception side frequency change amount; processing performed by said reception device to detect the synchronization signal using the calculated reception side candidate frequency; processing performed by said transmission device to calculate a transmission side candidate frequency which is a candidate for a frequency for transmitting the synchronization signal, based on the largest possible frequency change amount calculated on the basis of a bandwidth of the synchronization signal; processing performed by said transmission device to determine the transmission side candidate frequency as a synchronization signal frequency for transmitting the synchronization signal when the transmission side candidate frequency exists within the system frequency band; and processing performed by said transmission device to transmit the synchronization signal to said reception device using the synchronization signal frequency.
A communication system synchronizes a transmitter and receiver. The receiver searches for a synchronization signal by checking frequencies at progressively finer intervals (large to small). The transmitter sends the sync signal at the receiver's longest search intervals. The receiver narrows down its frequency search by stepping through frequency offsets, from large to small, calculating and testing candidate frequencies. The transmitter calculates candidate transmission frequencies based on the system bandwidth, and if a candidate falls within the allowed band, it uses that frequency to transmit the synchronization signal. The receiver calculates candidate frequencies for detection based on the reception side frequency change amount, and then checks each candidate frequency to detect the synchronization signal.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
June 4, 2007
July 16, 2013
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